Process of treating copper ores or copper-ore-mill tailings.



J. W. BEN N IE. PROCESS OF TREATING GQPPERVORES 0R COPPER ORE MILL TAILINGS. APiLIOATION TILED MAY 16, 1911.

1,019,708. Patented Mar. 5, 1912.

/ TRESTLE OVER LEICHING VATS W05 7' HEAP JOHN W. IBENNIE, OF CLIFTON, 'ARIZONA.

rnoonss or TREATING COPPER onns OR corrnnflonnn vnrn 'IA'ILINGS.

Specification of Letters Patent.

Application filed May 18. 1911. Serial No. 628,023.

.To all whom it may concern:

Be it known that I, JOIIN \V. Bnnmn, a subject of Great Britain, and a resident of Clifton, Arizona, have invented certain new and useful Improvements in-Processes of Treating Copper ()res or (loppenOre-hlill' Tailings, of which the following is a specification, accompanied by drawings.

This invention relates to a process of treating raw copper ores or copper ore mill railings, by lixiviation, or leaching, and the objects of the invention are to improve upon such process, and subject the ores (in-tailings to a preliminary treatment before being leached. I

Further objects of the invention will hereinafter appear and the drawing is a diagrammatic illustration of suitable apparatus for carrying out the process.

When iron pyrites or cuprous iron pyrites are subjected to slow roast or calcination, a part of their sulfur is given off in the form of sulfurous and sulfuric oXids, which in the presence of moisture form sulfurous and sulfuric acids. In accordance with my improved process, I subject siliceous copper ores, or copper ore mill ta'ilings to the gases given off in the calcination ofthe pyrites, preferably in the presence of moisture, thereby forming sulfites and sulfates with the copper oxids, carbonates and silicates in the oresor tailings. The copper in the ores or tailings existing as sulfids more readily becomes oxidized to sulfates when exposed to an atmosphere containing oxy v gen and sulfurous or sulfuric oxids in the presence .of moisture and heat, it ferrous I and ferric salts are also present. The quantity of sulfuric oxid and ferric salts formed is increased if ferrous salts, or ferrous salts and sodium chlorid, either in the .form 'of solution or solid crystals, are added to the pyrites or to the ores under treatment before ordurlng calclnation.

1n carrying out the process Wl11Cll Wlll be described in connection with the drawing, heaps of iron pyrites or cuprous iron pyrites A with proper ventilating channels B are built of anyshape that may be desired, as quadrangular, triangular or conical. These heaps .are ignited and as soon as calcination is started they are covered with the ores or materials C to be treated, care being taken that the covering'is built to sul'istantially conform with the shape of the pyrite heap and that proper precautions aroused in the building of ventilating openings throughout the heaps.

The rapidity of the combustion or calcination of the pyrites is regulated by means of the ventilating chimneys B. Calcination is preferably prolonged as much as possible, to insure a more complete roast of the py rites, thereby increasing the amount of ferric salts formed, and affording a longer time for the sulfurons and sulfuric oxids produced by thecombustion to react on the- 'lhe gases are allowed to permeate through the covering C without or in the presence of air and moisture, in order. to form sulfites or sulfates ofcopper from the original copper contents of the ores or mill tailings, while the oxids or iron in the copper ores or tailings form ferrous and ferric sulfates. The copper ores may contain, for instance, cuprous carbonate, hydrate, oxid or silicate, and the chemical reactions involved are as follows for a cuprous oxid ore. which will be selected by wa of example, it being understood that the reactions for other ores are analogous:

The copper salts formed by the reactions Patented Mar. 5, 1912.

are readily soluble inferric salts or dilute acid solutions.

Preferably while ealcination 1s proceedmg, a solution of ferrous sulfate'or a solution containing ferrous sulfate and sodium .ohlorid is added occasionally to the heaps,

in order to keep the ores moist. If the ferrous sulfate and sodium chlorid are added to the ironsulfids or cuprous iron sulfids before or during calcination, the chemical reactions involved in the roasting of the sulficlsmay'beexpressed.as tollows:

The ferrous sulfate or ferrous sulfate and sodium ehlorid, may also be added to the copper ores. or copper ore mill tail'ings or to both, before or during calcination of the: sultid'ores. with the same object. of increasing the quantities of sulfurous oxid and ferric salts forl'ned, and'in the copper ores ortailings under treatment the following reactions occur:

.or ei eso. rso..+euaci+oz F cnran so.

With cuproiis sulfids the reactions are as 40 follows:

. C11 5+2Fe C1 OuCI -PLFeCl PS e swmaso. -eonsoair soas I I The quantity of the ores or .ta-ilings to be treated and used as acovering C depends .on -the physical character and composition of 1 such ores or tailingsand may 'varyfrom five to twenty times the amount of iron sulfids or cuprous iron sulfids used. The more $111-- for in thesulfids the less the necessary quantity required. The more alkali and alkali earths in the copper ores, or copper ore mill tailings under treatment, the greater the quantity of sulfids'required. This applies also to the copper contents, since-the higher the .)ercentage of copper, the greater the quantity of sulfids required. 'The proportion of ferrous sulfate either in solid form or in solution, or in conjunction with sodium 'chl'orid, to be added, will also vary according to the composition of the ores or taili'ngs.

in practice. it has been found advisable to use about three tons of anhydrous 'ferrous sulfate to each ton of copper present in the ores or 'tailings. The process as will here-- iuafter appear is regeueratirc, in whiclrlhe efllueut. liquors from theprecipitation tanks.

fate requires], so that the quantities to be ans-ed may be regulated to meet the requirements of each particular ore.

' *Vith' some --ores or tailings better results may be obtained by using chlorids instead of sulfates. As stated, sodiinn-chlorid may be. used in conjunction with ferrous'sulfate and the quantity used will vary according to the ores or tailing's undertreatment. As will cipitation tanks. sozthat a. quantity equal to;

of the weight of the ores under treatment should be added. i

which may take from thirty to three hundred days, according to the size of the heaps andthe rapidity of the calcination, the outside covering of the heaps A, that is the ores ll under treatn'ient, may be treated in place. or remoi-"ed to tanks or' reservoirs and treated withwater or suitable leaching solutions of dilute sulfuric acid or ferric salts. The copper 'extracted from the ores forms a copper sulfate solution. and these copper sulfate' solutions may afterward be treated with metallic iron. in order to precipitate the copper. the iron passing into solution and forming ferrous sulfate. The ferrous sulfate is used as a part of the process in the treatment of the ores or tailing's before or during calcination. The roasted iron sulfids or cuprous iron sul'fids A are treated in a separate'tank E with a dilute solution of acid, which dissolves the salts formed during ealciuation'. This solution is'iised in dissolving the copper from the. ores or tailings G which have been subjected to the gases given off inc'alcinz'ition.

in order to illustrate the regenerative nature of the process, the a. )p aratus has been shown in' diagrammatic. form.

F represents a trestle over the roast heap.

heap over the leaching vats or tanks D and E. The leaching tanks l) are connectedby a pipe H with the vacuum tank J connected to the Vacuum pump. K operated by the motor L. The precipitating; launders O and I extend as shown. from the vacuum tank J to the collecting tank Q. From the collecting tank Q, pipes R and S lead to the pipe A pipe V leads from the sump to a point supply more than the necessary ferrous sul-' or not to exceed.onetenth of one per cent,

At the end of 'calk'zination off the pyrit'es,'-

ferrous and ferric salts'as well as the copper G represents a trestle extending from the T which in "turn leads to the sump pit-U.

above the roast heap, :as. shown; and this hereinafter appear, th'e chlorids will be returned with the-ellluent honors from the'preleaching tank E. A solution tank Y is connected with thepipe V and also connected at one end with the tank E by pipe a and at the other end bypipe b with the supply pipe 0 for the leaching tanks D. The pipe 0 is also connected with the tank E.

In carrying out the process the roasted sulfid ore A is leached in the tank E, while the ore C which has been subjected to the gases given off from the calcination of the ore A is leached in the tanks D. A car 6 carries the leachedore from the tanks D to the dump. The leached copper passes to the -vacuum tank J and thence to the precipitating launders O and P, and into the collecting tank. The sump contains principally ferrous salts in solution, which are supplied to the roast heap and also supplied to the solution tank Y and the leaching vats.

I claim and desire to obtain by Letters Patent the following:

1. The process substantially as herein described of treating raw copper containing ores or copper ore mill tailings. which comprises covering a roast heap of iron sultids or cuprous' iron sulfids with raw copper containing ores or copper ore mill tailings, without roasting said raw ores or tailings, and permitting the gases generated inrthe roast heap to permeate the raw ores or taillngs and react therewith in the presence of moisture,

leaching the so treated copper containing ores or tailings with a suitable leaching solu tion, and precipitating th copper from the solution.

2. The process substantially as herein described of treating raw copper containing ores or. copper ore mill tailings, which comprises covering a roast heap of iron sultids or cuprons iron sulfids with raw copper containing ores or copper ore mill tailings, without roasting said raw ores or tailings, and permitting the gases generated in the roast heap to permeate the raw ores or tailings and react therewith in the presence of ferrous sulfate, leaching the so treated copper containing ores or tailings with a suitable leaching solution, precipitating the copper from the solution, and returning the etlluent liquors after precipitation to tI f lSl1 quantity of the copper containing ores or tailings undergoing treatment.

3. The process substantially as herein described, of treating raw copper containing ores or copper ore mill tailings. which comprises covering a roast heap of iron sulfids or cuprous iron snlfids with raw copper containlng ores or copper ore mill ta lings, Wlllllout roasting said raw ores or ta1l1ngs and permitting the gases generated in the roast heap to permeate the raw ores or tailings and react therewith in the presence of ferrous sulfate and sodium chlorid, leaching the so treated copper containing ores or tail-l ings with a suitable leaching" solution, precipitating the copper from the solution, and

returning the etllnent liquors after precipitation to a fresh quantity of the copper containing ores or tailings undergoing treatment.

at. The process substantially as herein described, of treating raw copper containing ores or copper pre mill tailings, which comprises covering a roast heap of iron snlfids or cuprons iron sulfids with raw copper containing ores or copper ore mill tailings, without roasting said raw ores or tailings, and permitting the sulfurons and sulfuric oxids generated in the roast heap to permeate the-raw ores or tailings and react therewith, thereby forming sultites and sulfates of copper with the content of the cop per ores or tailings, then leaching the so treated copper ores or tailings with a suit.- able leaching solution of dilute acid or ferric salts, to produce a solution of copper sulfate, and finally precipitating copper from the solution.

The process substantially as herein de scribed, of treating raw copper containing ores or copper ore mill tailings, which comprises covering a roast heap of iron sultids or cuprous iron snlfids with raw copper containing ores or copper ore mill tailings, without roasting said raw ores or tailings, and permitting the sulfurous and sulfuric oxids generated in the roast heap to permeate the raw ores or tailings and react therewith, thereby forming sulfids and snl fates of copper with the content of the copper ores or tailings.

6. The process substantially as herein doscribcd, of treating raw copper containing ores or copper ore mill tailings, which coinprises covering a roast heap of iron sullids or cuprous iron sultids with raw copper containing ores or copper ore mill tailings, without roasting said raw ores or tailings, and permitting the gases generated in the roast heap to permeate the raw ores or tailings and react therewith.

7. The process substantially as herein described, of treating raw copper containing ores or copper ore mill tailings, which com-- prises covering a roast heap of iron sullitls or cuprous iron sulfids with raw copper containing ores or copper ore mill tailings, with out roasting said raw ores or tailings, and permitting the gases gt'aieratcd in the roast heap to permeate the raw ores or tailings and react therewith inthe presence of moisture and with access of air.

8. The process substantially as herein described, of treating raw copper containing ores or copper ore mill tailings. which com prises covering a roast heap of iron suliids or cnprous iron sulfide with raw copper containingores or copper ore mill tailings, without roasting said raw orcs or tailings. and permitting the gases generated in the roast heap to permeate the raw ores or tailings tJO and react therewith rous sulfate. Y 9. The process substantially as herein .de-

in the presence of fer-.

scribed, of treating raw copper containing ores or copper ore mill tailings, which comprises ,coverlngaroast heap of ron sulfids or ouprous'iron sulfids with raw copper containing ores orcopper ore mill'tailings, Withprises covering a roast heap of. iron sulfids or cuprous iron sulfids with raw copper'containing ores or copper ore mill tailings', Without roastingsaid raw ores or tailings, and

permitting-the gases generated in the roast heapto permeate the raw ores or 'tailings and react therewith in the presence of iron sulfate. I I

11. The process substantially as herein described, of treating raw copper containing ores or. copper ore mill tailings, which comprises covering a roast heap of iron sulfirls or cuprous iron sulfids with raw copper contaming ores orcopper ore mill tailings, with outroasting said raw ,or'es' or tailings, and permitting the gases generated in the roast heap to permeate the raw ores or tailings and react therewith in the. presence of iron sulfate and soolium chlorid.

In testimony whereofi I have signed this specification in the presence of two subscribing Witnesses. r

p JOHN W. BEN NIE. Witnesses:

P. D. RICE,,

B. F. SPRrGos.

Copies of this patent may-be obtained-for fl ve cents eao h, by address ing the Commissioner of .Patems,

Washington, O. 

